Heating Cables - What sort?

Hi everyone,

I'm building a under gravel heater for an engineering project at 
University.  I've built the power supplt and digital temperature 
controller, but I'm having trouble with the cables.  Apart from buying 
Dupla's own cables, which cost an absolute fortune here in Australia, 
what other cable can I use.  Nearly every cable you can buy is designed 
for lowest possible resistance, so is there a cable with a specific 
resistance per unit length?

I'm interested in what sort of cables Geoge Booth etc. used in their 

Thanks, Steve Amor
n1036416 at student_fit.qut.edu.au